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Oh where o where did our sun come from?

In episode 59, we talked about the “rare Earth hypothesis.” According to that school of thought, when and where a star is born, and when and where it lives, matters. Our Sun apparently showed up after a very active epic of star formation. This may have protected our baby solar system from being bathed by too much radiation. In addition, we orbit our galaxy in an area that has enough heavy elements for making rocky planets, but not too close to the overly hot and violent center of the milky way. Only, that’s not where we started. In fact, nobody is quite certain where we started, or how we got where we are now.

Here’s a NASA press release about the evolution of spiral galaxies, and evidence that suggests that stars were being born, around 10,000,000,000 years ago, at roughly 30 times the rate they are being born now.

Our Sun Came Late to the Milky Way’s Star-Birth Party

Here’s an article wherein a candidate for the birth place of our sun was eliminated from consideration, leaving us all scratching our heads.

Mystery Deepens Over Where Sun Was Born

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How to make a mind—part2

What we need is our rare and wonderful Earth, and approximately 4.54 billion years. Of course, that begs the question. How did we end up with our Earth, and how important is it that a planet is like our Earth to create intelligent tool users? According to the “Rare Earth Hypothesis,” to get minds, many highly improbable things, things that happened to our planet, must take place. Otherwise you don’t even get to create anything as complicated as a flatworm, let alone intelligent tool users. Over the next several episodes, as we examine how our planet gave rise to our species, we’ll revisit this hypothesis and consider which of many factors are necessary, rare, or common in our cosmos.

Here are a couple of articles with further details on the “Rare Earth Hypothesis.”

The “Rare Earth” Hypothesis

How Rare Is the Earth?

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Can’t we just look at it?

In episode 56 and episode 57, we looked at a couple of methods of detecting planets that are orbiting around stars other than our own sun. These methods involve a good deal of analysis and inference. Today, we learn about how astronomers can look directly at a planet around another star, once the overwhelming glare of the star is blocked out.

Since this is the last episode on finding exoplanets, here are a couple of links to pages about finding them, should you desire to dig a bit deeper.

Exoplanet Exploration: Planets Beyond our Solar System

5 Ways to Find a Planet

Planet Hunters

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The hunt for planet tomato

Unlike the method described in the previous episode, the transit method allows one to look at many stars at a time. When a planet crosses between us and the star it’s orbiting, the star’s light dims very slightly. If we can detect that dimming, we can detect said planet.

Here’s a link to the Kepler mission, that used the transit method to detect many extra solar planets, including some that are roughly Earth sized, apparently somewhat Earth like, and even orbiting in their star’s habitable zone—not too far or too close and thus possibly with liquid water, a prerequisite for life.

Kepler and K2 Missions

Here’s a link to a site where you can help for the hunt for extra solar planets.

Planet Hunters

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The stars wibble and wobble as their planets go round

There are several ways of detecting planets that orbit stars other than our sun. One method, called Doppler spectroscopy, relies on the fact that an orbiting planet causes its star to wobble. Spectrometers are used to observe the spectral lines within the stars light, (see episode 44,) and measure changes in their red shift or blue shift, (see episode 46,) as the star wobbles.

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The search for Planet 9

@AntonyTheReal_ showed me a video recently, in which one of the folks was rather upset with NASA. It bothered him that they were presenting details of a planet orbiting another star, lightyears away, while at the same time, we’re still not certain whether or not there is a ninth planet within our own solar system. Today, we talk about the possible ninth planet—why it’s thought that there is one, and why the search for it is taking so very long.

Here’s an article put out back in 2016, describing the reasons for searching for Planet 9.

Caltech Researchers Find Evidence of a Real Ninth Planet

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Irrational computers, investing, and racist robots

It’s easy to assume that computers and computer software, being without emotions, are more rational than we are. However, our software systems are like children of the mind, and they inherit our bias and irrationality. In fact, since they cannot judge context, they are less rational than we.

Here are a couple of talks on how computer programs, AKA. Algorithms, effect many aspects of our lives, despite being less than rational.

How algorithms shape our world

How I’m fighting bias in algorithms

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Complex analysis, the stock market, and seeing what you expect

Two theories about the stock market, the efficient market hypothesis and technical analysis, are each attempting to analyze the same complicated system—namely the stock market and the fluctuations of different share prices in different companies. Both theories start by assuming that the price always reflects all relevant information. Even though they both examine the same system, and start with the same assumption, they draw completely opposite conclusions. It’s just so terribly easy to see what you expect to see.

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More about the dark side

In 1933 Fritz Zwicky was studying the motion of galaxies within the Coma Cluster. He found that the motion could only be explained if there was considerably more mass present than what could be observed. Later, in the late 1970s, Vera Rubin was observing the rotational dynamics of the andromeda galaxy. She was attempting to verify theories of how such a galaxy should be spinning. Again, the motion didn’t fit the theory. Again, only having more mass there than could be observed could explain the motion. Thus, we have “dark matter”—a form of mass only observable by its gravitational effects.

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What is “dark energy,” and is there really such a thing?

In the early 1990s, two separate teams tracked the rate of expansion of the universe by using type Ia supernovas as standard candles, (see episode 41 and episode 42 for details on standard candle usage.) Each team found that the rate of expansion of the universe is increasing. Recent observations of type Ia supernovas suggest that they may not be as standard as previously thought. Although other observations have tended to support the notion of dark energy causing our universe to expand faster and faster, the analysis has been rather complicated, razing the possibility that the only reason we’ve seen more evidence for dark energy, is because we’ve expected it.

Here’s an article on how type Ia supernovas may not be as standard a standard candle as was believed.

Why Our Standard Candle Isn’t Really Standard

Here’s an article on the results of the boomerang experiment, thought to support the notion of dark energy; but only when combined with the now somewhat suspect supernova studies.

Balloon Flight Sees A Flat Universe Filled With Dark Energy

And here’s an article that suggests that the universe is expanding, but not accelerating, though it suffers from the same issues regarding complex analysis.

Marginal evidence for cosmic acceleration from Type Ia supernovae